GEMAS: establishing geochemical background and threshold for 53 chemical elements in European agricultural soil

The GEMAS (geochemical mapping of agricultural soil) project collected 2108 Ap horizon soil samples from regularly ploughed fields in 33 European countries, covering 5.6 million km2. The <2 mm fraction of these samples was analysed for 53 elements by ICP-MS and ICP-AES, following a HNO3/HCl/H2O (modified aqua regia) digestion. Results are used here to establish the geochemical background variation and threshold values, derived statistically from the data set, in order to identify unusually high element concentrations for these elements in the Ap samples. Potentially toxic elements (PTEs), namely Ag, B, As, Ba, Bi, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, Sn, U, V and Zn, and emerging ‘high-tech’ critical elements (HTCEs), i.e., lanthanides (e.g., Ce, La), Be, Ga, Ge, In, Li and Tl, are of particular interest. For the latter, neither geochemical background nor threshold at the European scale has been established before. Large differences in the spatial distribution of many elements are observed between northern and southern Europe. It was thus necessary to establish three different sets of geochemical threshold values, one for the whole of Europe, a second for northern and a third for southern Europe. These values were then compared to existing soil guideline values for (eco)toxicological effects of these elements, as defined by various European authorities. The regional sample distribution with concentrations above the threshold values is studied, based on the GEMAS data set, following different methods of determination. Occasionally local contamination sources (e.g., cities, metal smelters, power plants, agriculture) can be identified. No indications could be detected at the continental scale for a significant impact of diffuse contamination on the regional distribution of element concentrations in the European agricultural soil samples. At this European scale, the variation in the natural background concentration of all investigated elements in the agricultural soil samples is much larger than any anthropogenic impact

Use of GEMAS data for risk assessment of cadmium in European agricultural and grazing land soil under the REACH Regulation

Over 4000 soil samples were collected for the “Geochemical Mapping of Agricultural and Grazing Land Soil of Europe” (GEMAS) project carried out by the EuroGeoSurveys Geochemistry Expert Group. Cadmium concentrations are reported for the <2 mm fraction of soil samples from regularly ploughed fields (agricultural soil, Ap, 0 - 20 cm, N - 2218) and grazing land soil (Gr, 0 - 10 cm, N - 2127)

Introduction

This comprehensive text focuses on the increasingly important issues of urban geochemical mapping with key coverage of the distribution and behaviour of chemicals and compounds in the urban environment. Clearly structured throughout, the first part of the book covers general aspects of urban chemical mapping with an overview of current practice and reviews of different aspects of the component methodologies. The second part includes case histories from different urban areas around Europe authored by those national or academic institutions tasked with investigating the chemical environments of their major urban centers

Geochemical atlas of European groundwater : bottled water

Analysis of natural bottled mineral water (usually derived from untreated ground water) can provide a first impression of ground water chemistry at the European scale. For this study, 1785 bottled water samples were purchased from supermarkets, representing 1247 wells/springs/boreholes at 884 locations. These were analysed for 72 parameters by a variety of methods. A very strict quality control programme was followed to ensure results of high standard that are presented as a geochemical atlas. These give a first impression of European ground water geochemistry. Many processes are seen to affect the hydrogeochemical fingerprint of ground water, including rainfall chemistry, climate, vegetation and soil zone processes, mineral-water interactions, ground water residence time and the mineralogy and chemistry of the aquifer (and contamination). It appears that geology is the major factor controlling the content and distribution for the majority of elements in bottled water samples. However, knowledge of geology alone is inadequate to predict the hydrogeochemistry of bottled water. A key observation is that natural variation is enormous, usually three to four and for some elements up to seven orders of magnitude. It has also been found that bottle materials can have an influence on bottled water chemistry. For example, leaching of Sb from the bottle material is so serious that the results cannot be used as an indication of natural concentration in ground water. Very few analysed samples (in general <1%) returned values exceeding maximum admissible concentrations for “mineral water”, as defined by the European Commission

Geochemical atlas of European agricultural and grazing land soil (GEMAS Project)

The geochemical atlas of agricultural and grazing land soils (GEMAS) is a collaborative project of the EuroGeoSurveys Geochemistry Expert Group and the European Association of Metals (Eurometaux). The new European Chemicals Regulation (REACH), adopted in December 2006, and the proposed EU Soil Protection Directive, require additional knowledge about ‘soil quality’ at the European scale. The GEMAS project will deliver good quality and comparable exposure data of inorganic elements in agricultural and grazing land soil; in addition, soil properties, known to influence the bioavailability and toxicity of inorganic elements, will be determined. As inorganic elements occur naturally, industry dealing with natural resources requires this information to prove that it can produce its substances safely, which is a REACH requirement. Soil samples were collected at a density of one site per 2000 km2, according to an agreed field protocol. In total, 2211 samples of agricultural soil (0-20 cm), and 2118 samples from land under permanent grass cover (0 -10 cm) were collected. All samples were prepared in the same laboratory , and for the production of comparable results, they were analysed for the same suite of determinands in the same laboratory. A strict quality control programme was installed, and upon receipt of analytical results their quality was examined before their acceptance, and appropriate reports written. The mapped element distribution patterns are dominated by natural sources, geology and climate combined play ing a key role. The documentation of anthropogenic impact needs mapping at a much more detailed scale. 1 www

Chemical speciation and bioaccessibility of lead in surface soil and house dust, Lavrion urban area, Attiki, Hellas

In the Lavrion urban area study, Hellas, a five-step sequential extraction method was applied on samples of `soil (n = 224), affected by long-term mining and metallurgical activities, and house dust (n = 127), for the purpose of studying the potential bioaccessibility of lead and other metals to humans. In this paper, the Pb concentrations in soil and house dust samples are discussed, together with those in rocks and childrens blood. Lead is mainly associated with the carbonate, FeMn oxides and residual fractions in soil and house dust. Considering the very low pH of gastric fluids (13), a high amount of metals, present in soil (810152,000 mg/kg Pb) and house dust (41818,600 mg/kg Pb), could be potentially bioaccessible. Consequently, children in the neighbourhoods with a large amount of metallurgical processing wastes have high blood-Pb concentrations (5.9860.49 g/100 ml; median 17.83 g/100 ml; n = 235). It is concluded that the Lavrion urban and sub-urban environment is extremely hazardous to human health, and the Hellenic State authorities should urgently tackle this health-related hazard in order to improve the living conditions of local residents